1. Field of the Invention
The present invention relates to a video processing apparatus for detecting a face area from video data. More particularly, the present invention relates to a video processing apparatus for tracing a face area from the appearance to the disappearance of the face area, and a method of this processing and a program for causing a computer to execute this method.
2. Description of the Related Art
It is difficult to grasp the contents of video data in a short period of time unlike still image data. In order to grasp the contents of video data in a short period of time, techniques, such as high-speed reproduction, for example triple-speed playback, etc., a plurality of displays of thumbnails of predetermined scenes in video data, etc., are used.
However, it is hard to say that the contents of video data can be grasped in a short period of time using as high speed as triple-speed playback. On the other hand, if a reproduction speed is increased, there is a limit of a reproduction speed as long as human eyes can follow. Also, in the method of displaying thumbnails of predetermined scenes in video data, the scenes representing the characteristics of video data are not always displayed as thumbnails, and thus it is not sufficient to grasp the contents of the video data by the techniques.
In order to grasp the contents of such video data, it is effective to pay attention to a person appearing in the video data. In general, persons often appear in video data. In recent years, much research on face-detection techniques has been conducted. Technological developments have been carried out in order to grasp persons in video data using the face-detection techniques.
For example, there is a technique in which a moving object is detected from video data, a determination is made on whether the moving object is a person by a face-detection technique, and a predetermined number of frames are selected from the video data including that person to display the frames (for example, refer to Japanese Unexamined Patent Application Publication No. 2000-232638 (FIG. 1)). Also, there is a technique in which face areas are extracted from the frames forming video data, all the extracted face areas are grouped for each person, and a representative face area of that person is displayed from the grouped face areas (for example, Japanese Unexamined Patent Application Publication No. 2001-167110 (FIG. 1))